The Pilot Plan (Biotechnology) Unit combines several different types of activities. It is responsible for the large-scale production of bacteria, mammalian cells and biologically active compounds from various sources. Parallel to this activity, it is conducting process development work associated with these preparations In order to be able to execute them efficiently. In addition, the unit is carrying on research work not necessarily associated with a current project, but work that has long-term implications for the unit's performance. During the last year, the unit carried out 150 different large- scale preparations, including microorganism growth in volumes from 10 to 300 liters, mammalian cell growth up to 50 liter volumes and processing of various biological materials. Development work was done in the optimization of E. coli growth using the fed batch technique and oxygen-enriched air yielding 100 g/liter wet weight of biomass. A new method for the purification of Exotoxin A from pseudomonas aeruginosa was developed.